Semi-submersible support platform and positioning method thereof

ABSTRACT

A semi-submersible support platform and a positioning method thereof are disclosed. The semi-submersible support platform, used for operations at sea after sailed to a certain position of a sea surface, includes an upper deck and a lower pontoon. The upper deck and the lower pontoon are connected by a plurality of upright columns. Each upright column is provided with a support leg that is longitudinally inserted through the upright column. The lower pontoon has a plurality of chambers for receiving water therein. The support leg has a compartment for receiving water therein. Each upright column includes a leveling mechanism therein. When the support leg sinks to reach the seabed, the leveling mechanism in each upright column is combined with the support leg to support the support leg. The leveling mechanism can drive the upper deck to move up or down along the support leg.

FIELD OF THE INVENTION

The present invention relates to a support platform for operations at sea, and more particularly to a semi-submersible support platform and a positioning method thereof.

BACKGROUND OF THE INVENTION

For hanging operation at sea, there is a platform that can be used on the sea. After the platform is sailed to a certain position, it can be used for hanging operation at sea. In order to maintain stability during the hanging operation, especially to avoid vertical fluctuations caused by wind and waves on the platform, a positioning means is used for positioning the platform on the sea surface, which is conducive to the stability and safety of the hanging operation.

For example, U.S. Pat. No. 5,759,481 B1 and No. 7,815,398 B2 disclose a platform for operations at sea. A deck is provided with a plurality of legs. When the platform is sailed to a certain position, the legs are driven to move down to reach the seabed. The deck is lifted above the sea surface, thereby avoiding vertical fluctuations caused by wind and waves on the platform to maintain the stability of the platform. However, when the platform supported by the legs is moved out of the sea surface, the bottom of the platform will be lifted by the waves. When the waves recede, a vacuum will appear at the bottom of the platform to generate a force to attract the platform downwards, as if the weight of the platform is increased in an instant, so the legs sink further. The problem of the sinking of the platform caused by the waves will cause the instability of the height of the platform, which is unfavorable for operations at sea. In addition, the downward movement of the legs is completely dependent on a mechanical structure which must be able to lift the deck above the sea surface. Such a platform has the problems of heavy load and slow speed.

U.S. Pat. Publication No. RE29478 and No. 7219615 B2 disclose another platform for operations at sea. This platform belongs to a semi-submersible platform and has a lower pontoon below an upper deck. The lower pontoon can be filled with water to sink, and the center of gravity can be moved down toward the sea surface. The platform can be tightened by cables or steel cables to avoid vertical floating caused by wind and waves on the platform to maintain the stability of the platform. However, it has been found in practice that even if the center of gravity of the platform is moved down toward the sea surface and the platform is tightened by the cables or steel cable, the platform is still be vertically floating due to wind and waves, which will inevitably lead to instability during operations at sea. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a semi-submersible support platform and a positioning method thereof, which use support legs filled with seawater to sink to the seabed and a lower pontoon filled with seawater to move down toward the sea surface, thereby positioning the platform in an economical and stable manner.

In order to achieve the above object, the present invention provides a semi-submersible support platform and a positioning method thereof. The semi-submersible support platform, used for operations at sea after sailed to a certain position of a sea surface, comprises an upper deck and a lower pontoon. The upper deck and the lower pontoon are connected by a plurality of upright columns. Each upright column is provided with a support leg that is longitudinally inserted through the upright column. The lower pontoon has a plurality of chambers therein. The chambers are configured to receive water therein so that the lower pontoon can sink downwardly when the water is introduced into the chambers or float upwardly when the water is drained out. The support leg has a compartment. The compartment is configured to receive water therein so that the support leg can sink downwardly when the water is introduced into the compartment or float upwardly when the water is drained out. Each upright column includes a leveling mechanism therein. When the support leg sinks to reach the seabed, the leveling mechanism in each upright column is combined with the support leg to support the support leg. The leveling mechanism can drive the upper deck to move up or down along the support leg.

Preferably, the leveling mechanism located in each upright column has a plurality of upper positioning cylinders disposed in an upper seat and a plurality of lower positioning cylinders disposed in a lower seat. The upper seat and the lower seat are connected by a plurality of jacking cylinders. Each of the upper positioning cylinders and the lower positioning cylinders has a positioning rod that can be extended and retracted horizontally. The support leg supported by the leveling mechanism has positioning holes for receiving the positioning rods of the upper positioning cylinders and the lower positioning cylinders. The positioning rods of the plurality of upper positioning cylinders or the positioning rods of the plurality of lower positioning cylinders can be respectively extended into the positioning holes of the support leg. The lower seat can be driven close to or away from the upper seat by the plurality of jacking cylinders to drive the upper deck to move up or down.

As to the positioning method, after the semi-submersible support platform is sailed to the certain location of the sea surface, the compartment of the support leg is filled with water and then sinks to reach the seabed. The leveling mechanism in each upright column is combined with the support leg to support the support leg. After the plurality of chambers inside the lower pontoon are filled with water, the support leg inserted through each upright column sinks further. The leveling mechanism can drive the upper deck to move up or down along the support leg until the upper deck is horizontal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a planar schematic view of the platform in accordance with the present invention;

FIG. 2 is a planar schematic view of the upright column having the leveling mechanism and the wave-dissipating channel in accordance with the present invention;

FIG. 3 is a cross-sectional view of the wave-dissipating channels in the square upright columns of the two lower pontoons in accordance with the present invention;

FIG. 4 is a schematic view of FIG. 1, showing that the support legs are filled with water to sink;

FIG. 5 is a schematic view of FIG. 4, showing that the lower pontoon is filled with water to sink;

FIG. 6 is a schematic view of FIG. 2, showing that the positioning rods of the lower positioning cylinders of the leveling mechanism extend into the positioning holes of the support leg;

FIG. 7 is a schematic view of FIG. 6, showing that the jacking cylinders push the upper deck to move up; and

FIG. 8 is a schematic view of FIG. 7, showing that the positioning rods of the upper positioning cylinders extend into the positioning holes of the support leg.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a semi-submersible support platform and a positioning method thereof. The semi-submersible support platform is used for operations at sea after sailed to a certain position of a sea surface A. As shown in FIG. 1, the semi-submersible support platform comprises an upper deck 1 and a lower pontoon 2. The upper deck 1 and the lower pontoon 2 are connected by a plurality of upright columns 3. Each upright column 3 is provided with a support leg 4 that is longitudinally inserted through the upright column 3. The lower pontoon 2 has a plurality of chambers 21 therein. The chambers 21 are configured to receive water therein so that the lower pontoon 2 can sink downwardly when the water is introduced into the chambers 21 or float upwardly when the water is drained out. The support leg 4 has a compartment 41. The compartment 41 is configured to receive water therein so that the support leg 4 can sink downwardly when the water is introduced into the compartment 41 or float upwardly when the water is drained out. The compartment 41, in this embodiment, is located at the bottom of the support leg 4.

As shown in FIG. 2, each upright column 3 includes a leveling mechanism 5 therein. When the support leg 4 sinks to reach the seabed B, the leveling mechanism 5 in each upright column 3 is combined with the support leg 4 to support the support leg 4. The leveling mechanism 5 can drive the upper deck 1 to move up or down along the support leg 4. In this embodiment, the leveling mechanism 5 in each upright column 3 has a plurality of upper positioning cylinders 51. The upper positioning cylinders 51 are disposed in an upper seat 31. The leveling mechanism 5 further has a plurality of lower positioning cylinders 52. The lower positioning cylinders 52 are disposed in a lower seat 53. The upper seat 31 and the lower seat 53 are connected by a plurality of jacking cylinders 54. Each of the upper positioning cylinders 51 has a positioning rod 511 that can be extended and retracted horizontally. Each of the lower positioning cylinders 52 has a positioning rod 521 that can be extended and retracted horizontally. The support leg 4 supported by the leveling mechanisms 5 has positioning holes 42. The positioning holes 42 are configured to receive the positioning rods 511, 521. Thereby, the positioning rods 511 of the plurality of upper positioning cylinders 51 or the positioning rods 521 the plurality of lower positioning cylinders 52 can be respectively extended into the positioning holes 42 of the support leg 4. The lower seat 53 can be driven close to or away from the upper seat 31 by the plurality of jacking cylinders 54 to drive the upper deck 1 to move up or down.

As shown in FIG. 3, each upright column 3 is provided with a wave-dissipating channel 32 having through holes 321 on a plurality of sides of the upright column 3. The plurality of through holes 321 communicate with each other through a pipe 322 in the upright column 3. When the wave meet the upright column 3, the seawater flows in through one of through holes 321 and flows out through the other through holes 321 via the pipe 322 to eliminate the force of the wave against the upright column 3. As shown in FIG. 3, this embodiment has two lower pontoons 2. Each lower pontoon 2 has two upright columns 3 arranged in tandem.

The positioning method is that after the semi-submersible support platform is sailed to the certain location of the sea surface A, as shown in FIG. 4, the compartment 41 of the support leg 4 is filled with water and then sinks to reach the seabed B, the leveling mechanism 5 in each upright column 3 is combined with the support leg 4 to support the support leg 4. As shown in FIG. 5, after the plurality of chambers 21 inside the lower pontoon 2 are filled with water, the overall increased weight is greater than the buoyancy, and the support leg 4 inserted through each upright column 3 is further pressed downwardly (the support leg extends in the seabed B as shown in the figures) to be more stable. Each support leg 4 has an inconsistent degree of subsidence due to the different geological hardness of the seabed. When the upper deck 1 is inclined, the leveling mechanism 5 performs a horizontal fine adjustment for the upper deck 1. The leveling mechanism 5 can drive the upper deck 1 to move up along the support leg 4. At this time, as shown in FIG. 6, in this embodiment, the positioning rods 521 of the lower positioning cylinders 52 extend into the positioning holes 42 of the support leg 4, respectively. The positioning rods 511 of the upper positioning cylinders 51 are removed out of the positioning the holes 42. As shown in FIG. 7, the plurality of jacking cylinders 54 drive the upper seat 31 away from the lower seat 53 for driving the upper deck 1 to move up. As shown in FIG. 8, after the upper deck 1 is positioned, the positioning rods 511 of the upper positioning cylinders 51 extend into the positioning holes 42 to be positioned. On the contrary, for the downward movement, the positioning rods 521 of the lower positioning cylinders 52 respectively extend into the positioning holes 42 of the support leg 4, and the positioning rods 511 of the upper positioning cylinders 51 are removed out of the positioning holes 42, and the jacking cylinders 54 drives the upper seat 31 close to the lower seat 53 for driving the upper deck 1 to move down. Similarly, after the upper deck 1 is positioned, the positioning rods 511 of the upper positioning cylinders 51 extend into the positioning holes 42 to be positioned. The positioning of the upper deck 1 is performed by the aforementioned upward or downward movement until the upper deck 1 is horizontal for operations at sea.

From the above description, the advantages of the present invention are described below. The upright columns 3 are connected between the upper deck 1 and the lower pontoon 2. The support leg 4 is inserted through the upright column 3. After the support leg 4 is filled with water, it sinks to reach the seabed B. The leveling mechanism 5 disposed in the upright column 3 is combined with the support leg 4. After the lower pontoon 2 is filled with water, the center of gravity is moved down toward the sea surface A, so that the support leg 4 is stably supported on the seabed B. The upper deck 1 is moved up or down to a horizontal position. When the support leg 4 is filled with the seawater and sinks to the seabed B, the buoyancy of the lower pontoon 2 is sufficient to support the entire weight including the upper deck 1 and the lower pontoon 2, so that the upper deck 1 is maintained to be above the sea surface. When the aforementioned overall weight and the buoyancy of the lower pontoon 2 are balanced, the leveling mechanism 5, with the aid of the buoyancy of the lower pontoon 2, can easily elevate or lower the upper deck 1 with buoyancy along the support leg 4. This is beneficial for the horizontal fine adjustment of the upper deck 1 to achieve the effect of stable positioning of the platform. Besides, the sinking of the lower pontoon 2 and the support leg 4 is caused by injecting seawater, rather than a drive mechanism used for lifting, thereby saving cost and being economical.

Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. A semi-submersible support platform, used for operations at sea after sailed to a certain position of a sea surface, comprising an upper deck and a lower pontoon, the upper deck and the lower pontoon being connected by a plurality of upright columns, each upright column being provided with a support leg that is longitudinally inserted through the upright column, the lower pontoon having a plurality of chambers therein, the chambers being configured to receive water therein so that the lower pontoon can sink downwardly when the water is introduced into the chambers or float upwardly when the water is drained out, the support leg having a compartment, the compartment being configured to receive water therein so that the support leg can sink downwardly when the water is introduced into the compartment or float upwardly when the water is drained out; each upright column including a leveling mechanism therein, wherein when the support leg sinks to reach the seabed, the leveling mechanism in each upright column is combined with the support leg to support the support leg, the leveling mechanism can drive the upper deck to move up or down along the support leg.
 2. The semi-submersible support platform as claimed in claim 1, wherein each upright column is provided with a wave-dissipating channel, the wave-dissipating channel has through holes on a plurality of sides of the upright column, the plurality of through holes communicate with each other through a pipe in the upright column, when a wave meets the upright column, seawater flows in through one of through holes and flows out through the other through holes via the pipe to eliminate the force of the wave against the upright column.
 3. The semi-submersible support platform as claimed in claim 1, wherein the leveling mechanism located in each upright column has a plurality of upper positioning cylinders disposed in an upper seat and a plurality of lower positioning cylinders disposed in a lower seat, the upper seat and the lower seat are connected by a plurality of jacking cylinders, each of the upper positioning cylinders and the lower positioning cylinders has a positioning rod that can be extended and retracted horizontally, the support leg supported by the leveling mechanism has positioning holes for receiving the positioning rods of the upper positioning cylinders and the lower positioning cylinders, the positioning rods of the plurality of upper positioning cylinders or the positioning rods of the plurality of lower positioning cylinders can be respectively extended into the positioning holes of the support leg, the lower seat can be driven close to or away from the upper seat by the plurality of jacking cylinders to drive the upper deck to move up or down.
 4. A positioning method of the semi-submersible support platform as claimed in claim 3, wherein after the semi-submersible support platform is sailed to the certain location of the sea surface, the compartment of the support leg is filled with water and then sinks to reach the seabed, the leveling mechanism in each upright column is combined with the support leg to support the support leg, after the plurality of chambers inside the lower pontoon are filled with water, the support leg inserted through each upright column sinks further, the leveling mechanism can drive the upper deck to move up or down along the support leg until the upper deck is horizontal; for the upper deck to move up, the positioning rods of the lower positioning cylinders respectively extend into the positioning holes of the support leg, and the positioning rods of the upper positioning cylinders are removed out of the positioning the holes, and the plurality of jacking cylinders drive the upper seat away from the lower seat for driving the upper deck to move up, after the upper deck is positioned, the positioning rods of the upper positioning cylinders extend into the positioning holes to be positioned; for the upper deck to move down, the positioning rods of the lower positioning cylinders respectively extend into the positioning holes of the support leg, and the positioning rods of the upper positioning cylinders are removed out of the positioning holes, and the jacking cylinders drives the upper seat close to the lower seat for driving the upper deck to move down, after the upper deck is positioned, the positioning rods of the upper positioning cylinders extend into the positioning holes to be positioned.
 5. A positioning method of the semi-submersible support platform as claimed in claim 1, wherein after the semi-submersible support platform is sailed to the certain location of the sea surface, the compartment of the support leg is filled with water and then sinks to reach the seabed, the leveling mechanism in each upright column is combined with the support leg to support the support leg, after the plurality of chambers inside the lower pontoon are filled with water, the support leg inserted through each upright column sinks further, the leveling mechanism can drive the upper deck to move up or down along the support leg until the upper deck is horizontal. 